I compulsively use synthetic oil in my truck, but the oil my dealer carries for my motorcycle is conventional. I'm wondering where everyone stands on the synthetic vs. conventional debate, and if you vote synthetic, which synthetic do you use?

i have a 2009 Ninja 650R, if that matters in anyone's decision

 

The oil question is similar to politics and religion. You may want to do a search first. lol But since you are already familiar with synthetics, then the question really falls into your lap. Mileage, brand of oil, etc. Welcome to KF

 

I prefer synthetics due to their superior resistance to high-heat coking and sludging. Even the best conventionals turn to tar under the heat that synthetics can withstand. I also prefer them due to their ability to remain thin when temperatures drop.

On the other side of the coin, if parts of your engine are getting hot enough to coke conventional oil, there's likely a mechanical or design problem. I attribute my preference to what I've seen inside of 50,000 + mile car engines after a lifetime on conventional, when there are hotspots or other anomolies such as the last-generation Toyota Camry V6. There were hot and cool spots all over the cylinder heads in that car, and while THAT condition didn't compromise engine longevity, conventional oil's inability to cope contributed to widespread engine failures when the cylinder heads were overcome by sludge.

So, as a safety measure against the unknown, I prefer to use synthetics to bare the brunt of the Texas heat, stop & go traffic, etc. My sister has 135,000 trouble-free miles on her 2001 Toyota Tacoma in Georgia, fed Mobil 1 since new. I don't own a high-mileage car, but I've never had issues either in any of the 17 cars I've owned.

To confuse you even more...I stopped running synthetic in my 08 Ninja 250 because of shift feel. It felt and sounded like the gears were slamming against each other during shifts, and Rotella 15W-40 put an end to a lot of that. It may not have been hurting anything, but I couldn't stand the sound, so that bike wasn't treated to syn oils.

 

I switched to synthetic like 13,000 miles ago, and its been perfect. I also run Amsoil full synthetic 10,000 mile oil in my Dodge.

 

hehehehehe

 

Mobil-1 in all my vehicles.
Use Schaeffer syn gear oils in differentials, transfer case, steering pins on the Rover and Pathfinder. Both have 150K on them and run like new.

 

I've run bikes for over 100,000 miles on old style dino oil without ever needing to do anything more than routine maintenance. I also change the oil a lot less frequently than most Americans.

That said, I use semi-synth in my diesel car, because it's what the dealer puts in; dealer service every 12,500 miles to maintain the warranty, and in my bike I use fully synth for a wholly pragmatic reason. The local Halfords sells its own brand fully synthetic motorcycle oil in 2 litre containers. This is just enough for an oil change and is actually cheaper than buying 2 x 1 litre of any other oil, and saves having half used cans lying around the garage if I buy a gallon.

In my experience, if the bike is used regularly for decent length journeys and the oil is changed by the book, it doesn't really matter what you use as long as it's the right grade. For the 650R the book interval is 7,500 miles. My dealer tells me that Kawasaki are happy with an annual oil change, or every 12,000 miles if you do more than 12,000 miles in a year.

Just as an aside, recent research indicates that oil gives better protection after it's been in for a couple of thousand miles and the protection stays good for at least 25K miles. That's on heavily used vehicles though, and doesn't take into account the effects of contaminants dropping out of suspension in a vehicle that stands for fairly long periods of time. It also doesn't take account of the gears chopping up the long chain molecules of oil circulating in a bike gearbox. Based on that, you could be doing your bike no favours at all if you change the oil too often, but as it's unclear whether the research can be safely applied to bikes, my advice is to go by the book, or anything else that the manufacturer might say, as far as oil change intervals are concerned.

Rob

 

I just switched to synthetic at around 17,000mi (a month ago) and after about 1500mi of riding my average mileage went up about 12% from around 50mpg to around 56mpg in mixed riding. And I did notce the the clunking and shift feel that 94Ninja250 noticed also (I ride a '88 250 Eliminator), so much so I took it to the shop thinking the gearbox was about to gernade. Realy CLUNKS into first, and the shifts feel less positive. I also just rode through the Laurel Highlands this past weekend, about 260mi of twisty "mountain riding" and averaged 67.5mpg for the day, but the 95mi each way on the highway and running a 15T front sproket helped. My shop charges $12 for the same Castrol motorcycle syn that the auto parts store charges $8 for. But make sure it's motorcycle specific synthetic oil, they are not interchangeable.